Sensor based on a Pt/LaF3/SiO2/SiC structure for the detection of chlorofluorocarbons

A metal-insulator-semiconductor structure based on silicon carbide with a s ubgate layer of LaF3 solid electrolyte is discussed as a gas sensor. The ki netics of the variation of the flat-band potential of a Pt/LaF3/SiO2/SiC st ructure in interaction with chlorofluorocarbons (Freons) is investigated in the temperature range from 300 to 530 degrees C. The activation energies o f the gas sensitivity are estimated from the temperature dependences of the response rate of the sensor to various Freons. The possibility of detectin g all the investigated chlorofluorocarbons at a concentration level of 10 p pm in air is demonstrated. (C) 1999 American Institute of Physics. [S1063-7 842(99)01411-7].